It is sometimes necessary to lower or remove a fuel tank from a car when the tank is corroded or to:
- Replace fuel or vapor hoses.
- Repair a fuel tank sending unit.
- Replace an in-tank electric fuel pump.
Fuel tank repair is commonly done by radiator shops. Possible repairs include flushing, welding, and treating with "slushing compound" to seal and protect the inside of the tank. Because of the danger associated with gasoline, many repair shops choose not to make tank repairs. The information provided here is included as a precaution for those who choose to remove fuel tanks.
Fuel Tank Draining
Always drain gasoline into an approved container, and use a funnel to avoid gasoline spills.
Before removing a fuel tank, fuel should be pumped from the tank using commercial fuel handling equipment.
Equipment for the safe handling of fuel.
- The fuel is pumped out, either through the fill opening or through the outlet line to the fuel pump.
- Then raise the vehicle on a hoist.
- Make sure you have an approved gasoline container and are prepared to catch all of the fuel before proceeding.
- If the tank has a drain bolt, remove it to drain the fuel. If the fuel tank does not have a drain bolt, locate the fuel tank drainpipe or filler pipe.
- Using the proper adapter, connect the intake hose from a hand-operated or air-operated pump to the pipe.
- Insert the discharge hose from the hand-operated or air-operated pump into an approved gasoline container, and operate the pump until all the fuel is removed from the tank.
- After draining a fuel tank, seal all openings.
Abide by local laws for the disposal of contaminated fuels. Be sure to wear eye protection when working under the vehicle.
When servicing fuel system components, always place a Class B fire extinguisher near the work area.
Removing a Fuel Tank for Servicing
The procedure for removing a fuel tank varies depending on the vehicle make and year. Always follow the procedure in the vehicle manufacturer's service manual.
Wear safety glasses and do not use a drop light. Liquid falling on the hot glass can cause the bulb to explode. If it is accidentally dropped or has a bad switch or loose connections, it can cause a fire.Work in a well-ventilated area, with no possible source of ignition, such as running cars or electrical equipment.
- Before removing the tank, remove the battery ground cable to avoid an accidental spark.
- Relieve the fuel system pressure, and drain the fuel tank.
- Gasoline weighs about 7 pounds per gallon. A full tank could easily weigh in excess of 100 pounds. Attempting to remove it while it is full could result in a dangerous gasoline spill or an injury. Remember, gasoline vapor is extremely flammable.
- Raise the vehicle on a hoist, or lift the vehicle with a floor jack and then lower the chassis onto jack stands.
- Use compressed air to blow dirt from the fuel line fittings and wiring connectors.
- Remove the fuel tank wiring harness connector from the body harness connector.
- Remove the ground wire retaining screw from the chassis if there is one.
- Disconnect the fuel lines from the fuel tank. If these lines have quick-disconnect fittings, follow the manufacturer's recommended removal procedure in the service manual. Some quick-disconnect fittings are hand releasable, and others require the use of a special tool.
Some quick-connect fittings require the use of a special tool to separate them.
- Wipe the filler pipe and vent pipe hose connections with a shop towel, and then disconnect the hoses from the filler pipe and vent pipe to the fuel tank.
- Unfasten the filler from the tank. If it is a rigid one-piece tube, remove the screws around the outside of the filler neck near the filler cap. If it is a three-piece unit, remove the neoprene hoses after the clamp has been loosened.
Typical location of a fuel tank's filler tube. Courtesy of DaimlerChrysler Corporation.
Do not heat the bolts on the fuel tank straps in order to loosen them. The heat could ignite the fumes.
- Loosen the bolts holding the fuel tank straps to the vehicle until they are about two threads from the end.
Front and rear fuel tank strap mounting bolts. Courtesy of General Motors Corporation - Oldsmobile Division.
Gas tanks should be filled with an inert gas, such as CO2, before any welding takes place. Even if a tank has been thoroughly flushed of gasoline, the tank may still contain flammable vapors. Attempting to weld such a tank may result in an explosion.